Fatigue is a known problem in the transportation industry. Operators can become fatigued after extended periods of time of machine control. Some machines require repetitive movements from the operator that can be tiring, while other machines require very little operator movement that can result in drowsiness. In either situation, the operator may lose some ability to concentrate and the operator's attentiveness may dull. This can result in improper machine control, delayed machine control, or lack of machine control. Any of these results can cause a loss in productivity, profitability, and safety.
One exemplary system for helping an operator stay alert is commonly known as a vigilance control device. A vigilance control device includes lights and sounders that are connected to timers. The operator is required to provide some type of input with a minimum frequency that is controlled by the timers. If the input is not received within a particular time period, a warning in the form of a flashing light or a sounding siren is initiated. If the operator still does not provide any input, the vigilance control device automatically implements a penalty in the form of a machine speed reduction or activation of the machine's brakes. Such a system is described in a publication by the Man Vehicle Laboratory of the Massachusetts Institute of Technology titled “Locomotive In-Cab Alerter Technology Assessment” that published on Nov. 20, 2006 (the “Alerter Publication”).
In addition to describing conventional activity-based Alerters, the Alerter Publication also describes a new type of Alerter that automatically detects operator fatigue without operator input. In particular, the automatic Alerter relies on video images of the operator, and uses computer machine vision algorithms to identify specific features in the video images (e.g., head pose, gaze direction, and eyelid position). Based on these features, the automatic Alerter then generates the warnings and/or penalty described above.
While the conventional Alerter and the automatic Alerter may both provide some benefit in keeping an operator vigilant and alert, they both suffer drawbacks. For example, the conventional Alerter has been determined to encourage preemptive behavior that avoids activation of startling warnings. In addition, it has been found that train operators can, over time, become accustomed to providing input to the Alerter as a reflexive activity that does not require concentration and that can even be done while asleep. Further, the automatic Alerter can sometimes misread an operator's face, particular when lighting conditions are poor, when the operator is wearing glasses, or during other similar conditions.
The present disclosure is directed at overcoming one or more of the shortcomings set forth above and/or other problems of the prior art.